Mixtures of rubbers and activated and hydrophobic oxidic and siliceous fillers and a process for their preparation

Abstract

The present invention relates to rubber compounds comprising one or more soluble rubbers, hydrophobized filler, and one or more sulfane-silane compounds on an inorganic or organic support and to a process for making them. The novel rubber compounds are suitable for moldings of every kind, especially tires or tire treads having low rolling resistance and high resistance to abrasion.

What is claimed is:  
     
       1. Rubber compounds comprising one or more soluble rubbers, 5 to 500 phr of hydrophobized filler having a methanol wettability of 1 to 60 weight percent, and 0.1 to 40 phr of one or more polysulfidic-silane compounds on an inorganic or organic support wherein said polysulfidic-silane compounds on an inorganic or organic support are those prepared by the reaction of (haloalkyl)silanes (I) and, if required, organic halogen compounds (II) with polysulfides (III) in water at temperatures in the range of 20-220° C. in the presence of an organic or inorganic support, the mole ratios of the components (I):(II):(III) depending on the number of bound halogen atoms in such a way that there are from 1.5 to 3 halogen atoms to every molecule of polysulfide, and the mass ratio of the polysulfidic-silane compound to support being from 0.1 to 10. 
     
     
       2. Rubber compounds according to claim  1  in which said soluble rubber is selected from the group consisting of a polybutadiene, styrene-butadiene copolymer, isobutene-isoprene copolymer, ethylene-propene-diene copolymer, polyisoprene, or natural rubber. 
     
     
       3. Rubber compounds according to claim  1  in which said hydrophobized filler is hydrophobized oxide or silicate fillers or mixtures of the two. 
     
     
       4. Rubber compounds according to claim  1  in which said filler is not wetted by water when they are in the dry state at room temperature but is wetted by a water/methanol mixture containing from 1 wt % to 60 wt % methanol. 
     
     
       5. Rubber compounds according to claim  3  in which said oxide or silicate fillers or mixtures of the two have been hydrophobized in water. 
     
     
       6. Rubber compounds according to claim  3  in which said oxide or silicate fillers or mixtures of the two have been hydrophobized while in the dry state. 
     
     
       7. Rubber compounds according to claim  1  where the formulae said (haloalkyl)silanes (I), organic halogen compounds (II), and polysulfides (III) correspond to the following 
       
         
           R 1 R 2 R 3 Si.XHal n  (I)  
         
       
       
         
           YHal m  (II)  
         
       
       
         
           Me 2 S x  (III),  
         
       
       where: 
       R 1 , R 2 , and R 3  are identical or different substituents, and may be chlorine atoms, alkyl or alkoxy groups having from 1 to 18 carbon atoms, some of which may be replaced by oxygen, nitrogen, or sulfur atoms, aryl or aryloxy groups having from 6 to 12 carbon atoms, or alkylaryl or alkylaryloxy groups having from 7 to 18 carbon atoms, provided that at least one of the substituents R 1 , R 2 , and R 3  is chlorine, an alkoxy group, aryloxy, or an alkylaryloxy group;  
       X represents linear, branched or cyclic, optionally unsaturated C 1 -C 18 -alkylene groups, which may optionally be interrupted by oxygen atoms, and wherein one to three hydrogen atoms might be substituted by halogen atoms,  
       Y is either a monovalent, bivalent, or trivalent heteroatom or a linear or branched, saturated or unsaturated aliphatic hydrocarbon substituent group, or an aromatic one, having from 1 to 4 free valencies and from 1 to 36 carbon atoms, which may be replaced by one or more oxygen, nitrogen, or sulfur atoms or be substituted with aryl (C 6 -C 12 ), alkoxy (C 1 -C 12 ), R-oxycarbonyl (C 1 -C 22 ), R-carbonyloxy (C 1 -C 22 ), hydroxy, cyano, amino, carboxyl, sulfo, carboxylato, or sulfonato groups;  
       m is an integer whose value is from 1 to 4;  
       n is an integer whose value is from 1 to 3:  
       x is an integer whose value is from 1 to 8;  
       Hal is fluorine, chlorine, or bromine; and  
       Me is ammonium or a metal cation.  
     
     
       8. A process for the preparation of rubber compounds comprising one or more soluble rubbers, 5 to 500 phr of hydrophobized filler having a methanol wettability of 1 to 60 weight percent, and 0.1 to 40 phr of one or more polysulfidic-silane compounds on an inorganic or organic support in which said polysulfidic-silane compounds on said inorganic or organic support is mixed with a rubber solution and said hydrophobized filler and water and solvent are removed at a temperature in the range of 50-250° C. wherein said polysulfidic-silane compounds on an inorganic or organic support are those prepared by the reaction of (haloalkyl)silanes (I) and, if required, organic halogen compounds (II) with polysulfides (III) in water at temperatures in the range of 20-220° C. in the presence of an organic or inorganic support, the mole ratios of the components (I):(II):(III) depending on the number of bound halogen atoms in such a way that there are from 1.5 to 3 halogen atoms to every molecule of polysulfide, and the mass ratio of the polysulfidic-silane compound to support being from 0.1 to 10. 
     
     
       9. A process according to claim  8  in which said rubber solution contains further fillers or auxiliaries to assist processing or stabilization. 
     
     
       10. A process according to claim  8  in which said solvent is removed by steam distillation. 
     
     
       11. A molded product comprising rubber compounds comprising one or more soluble rubbers, 5 to 500 phr of hydrophobized filler having a methanol wettability of 1 to 60 weight percent, and 0.1 to 40 phr of one or more polysulfidic-silane compounds on an inorganic or organic support wherein said polysulfidic-silane compounds on an inorganic or organic support are those prepared by the reaction of (haloalkyl)silanes (I) and, if required, organic halogen compounds (II) with polysulfides (III) in water at temperatures in the range of 20-220° C. in the presence of an organic or inorganic support, the mole ratios of the components (I):(II):(III) depending on the number of bound halogen atoms in such a way that there are from 1.5 to 3 halogen atoms to every molecule of polysulfide, and the mass ratio of the polysulfidic-silane compound to support being from 0.1 to 10. 
     
     
       12. A molded product according to claim  11 , wherein said soluble rubber is selected from the group consisting of a polybutadiene, styrene-butadiene copolymer, isobutene-isoprene copolymer, ethylene-propene-diene copolymer, polyisoprene, or natural rubber. 
     
     
       13. A molded product according to claim  11 , in which said hydrophobized filler is hydrophobized oxide or silicate fillers or mixtures of the two. 
     
     
       14. A molded product according to claim  11 , in which said filler is not wetted by water when they are in the dry state at room temperature but is wetted by a water/methanol mixture containing from 1 wt % to 60 wt % methonal. 
     
     
       15. A molded product according to claim  14  in which said oxide or silicate fillers or mixtures of the two have been hydrophobized in water. 
     
     
       16. A molded product according to claim  13  in which said oxide or silicate fillers or mixtures of the two have been hydrophobized while in the dry state. 
     
     
       17. A molded product according to claim  11  wherein said molded product is a tire. 
     
     
       18. A molded product according to claim  11  wherein said molded product is a tire tread.